The invention relates to a mining vehicle comprising at least one electric component, apparatus or machine operating at alternating voltage and having a specific nominal voltage, a connection cable for the power supply to the mining vehicle, a cable reel for the connection cable, connecting means for connecting the mining vehicle to an alternating current network, and a transformer arranged to transform the voltage level of the alternating current network into the nominal voltage.
Further, the invention relates to a method for energy supply to a mining vehicle, the mining vehicle comprising at least one electric component, apparatus or machine operating at alternating voltage and having a specific nominal voltage, whereby the method comprises supplying power to the mining vehicle from an alternating current network with a specific voltage level, the mining vehicle having a transformer by means of which the voltage level of the alternating current network is, as required, transformed into the nominal voltage.
The operation devices of rock drilling rigs are typically electrically operated. Thus, at least at the work sites during the working stages, the rock drilling rig is connected to an electric network. Particularly on tunnel work sites and in other objects of contract work, the rock drilling rig is used for rather a short time of its whole life span, and after it has been used on one work site, it is transferred to another one. Transfer from one work site to another will only be successful if the voltage levels of the electric networks on the work sites are the same. If the voltage levels of the electric networks on different work sites are different, the voltage level should be transformed by a transformer to be suitable for the operation device of the rock drilling rig but, in practice, the size of the required transformer and thus the difficulty to handle it and the subsequent costs are so great that rock drilling rigs are only used at work sites where the voltage level of the electric network feeding them is suitable for their operation devices. Further, the rock drilling rig could be transformed to have a suitable voltage level by changing electric components, such as protective switches, contactors, cables and motors to suit the voltage level of the electric supply network. Also this alternative is, in practice, far too difficult to be implemented.
Publication WO2011/080391 discloses a rock drilling rig with electrically operated operation devices, and means for connecting the rock drilling rig to an electric network. The rock drilling rig comprises electrically operated operation devices with two different voltage levels, some of them being fed directly from the electric network and some through a transformer. The rock drilling rig can be operated while being connected to at least two electric networks having different voltage levels. The transformer does not have to be of a very large size because only some of the operation devices of the rock drilling rig need to be fed through it. Nevertheless, electrically operated operation devices with two different voltage levels must be used in the rock drilling rig.